1. Field of the Invention
The invention relates to an article of footwear, in particular a sports shoe, and more particularly a shoe adapted for athletics, sport walking, or cycling. Footwear according to the invention can have a high upper or low upper.
2. Description of Background and Other Information
Footwear of the aforementioned type can be used in fields such as walking, running on flat or mountainous terrain, on-road and off-road cycling, roller skating, snowboarding, ball-playing sports, or the like, whether having a high upper or low upper and whether referred to as a boot or a shoe. In the following description, the use of the terms footwear, boot, and shoe are to be considered interchangeable and not to be construed as limiting, one relative to the other, unless stated otherwise.
It is always desirable for the shoe to be lightweight, whether it has a low upper or a high upper. Indeed, walking, racing or pedaling movements induce accelerations and decelerations of each foot. The lightness reduces the inertia of the shoe and, consequently, there is less fatigue from using the shoe.
It is also desirable for the foot to be well supported in the shoe, i.e., with little or no clearance. This is true for walking or running shoes, because supports must be firm. This is also true in cycling, in particular during pulling motions of the leg. Indeed, at the time when a tensile force is exerted, the foot tends to move away from the sole. This undesired movement reduces pedaling efficiency.
It is also desirable that the shoe protect the foot so that no or very few injuries occur, even during an intensive and/or prolonged sporting use.
In addition it is advantageous to provide the shoe with an attractive appearance, which promotes sales, for example. But the problem is to improve the aesthetics without penalizing the technical characteristics.
The prior art has proposed shoes that seek to optimize the aforementioned characteristics. However, it has not been possible to optimize all of them, at least simultaneously. For example, shoes specifically adapted to run a marathon can be used for only one race, because they are too fragile.
For example, a shoe that is too light becomes fragile. Conversely, a stronger shoe tends to be too heavy and not very flexible, as it is made of thicker or more rigid materials, which negatively affects foot support. Consequently, the efficiency of a stride or of a pedaling movement is reduced. Moreover, injuries can occur during intensive use.